There were hundreds of prisoner of war camps in the UK during the second world war. Prisoner of war camps in the UK: German PoWs somewhere in England bring in the harvest. Photograph: Hulton Archive/Getty Images What would happen if the UK's prison population suddenly increased by 400,000 people? That's what occurred between 1939 and 1948, when thousands of Germans, Ukranians and others became Britain's prisoners of war, according to a new book.The camps where the PoWs were imprisoned have largely (but not all) disappeared. At one time hundreds of them were spread across the UK.The best known was Island Farm in Wales - scene of a 'great escape' in 1945, with some German POWs getting as far as Birmingham and Southampton.Author Sophie Jackson has written a book, Churchill's Unexpected Guests, examining this overlooked period of Britain's history, looking at what happened to every camp from the period. "